The present invention relates to powdered aerosol compositions. More particularly, this invention relates to powdered aerosol compositions having improved application characteristics.
Aerosol sprays are now widely used, particularly in the cosmetic, topical pharmaceutical and detergent fields, for delivery of an additive such as a cosmetic, pharmaceutical, or cleaning composition to a substrate such as the skin or other surface to be treated. Aerosol compositions are widely used as antiperspirants to direct the antiperspirant to the skin in the form of a finely divided spray.
Aerosol antiperspirant compositions typically are anhydrous systems comprising an antiperspirant salt dispersed in a liquid vehicle together with a liquefied volatile propellant in a pressurized aerosol container. The aerosol spray is created by the rapid boiling of the propellant upon dispensing from an atomizing valve. Such aerosol containers are described, for example, in U.S. Pat. Nos. 3,083,917, 3,083,918 and 3,544,258.
Fine sprays dispersed from a container containing a powdered aerosol composition can give rise to stable aerosols of finely divided liquid particles, referred to as mistiness, and further can produce a fine dust of suspended solids which settles only slowly, referred to as dustiness. A drawback associated with aerosol compositions is that they can create excessive dustiness or mistiness during application.
Excessive mistiness and dustiness of an aerosol composition can lead to waste in that less of the composition reaches its intended target, and, further, can result in an increase in airbourne particles which has a deletorious effect on the environment and makes breathing near the application site more difficult.
Attempts have been made in the art to produce aerosol antiperspirant compositions having reduced mistiness and dustiness upon application. For example, U.S. Pat. No. 4,806,338 to Smith discloses an aerosol antiperspirant composition purportedly having improved application, cosmetic and performance characteristics, wherein the composition contains a particulate antiperspirant, a functionalized siloxane, an aerosol propellant, and optionally a silicone gum, a volatile silicone oil, and a bulking agent.
U.S. Pat. No. 4,152,416 to Spitzer et al. (Spitzer) disclose an aerosol antiperspirant composition reported to be capable of being dispensed from aerosol containers with low mistiness and dustiness. The Spitzer composition contains an antiperspirant salt, a liquefied propellant, a bulking agent a synthetic polymer gum which may be a silicone gum, and optionally a nonvolatile liquid such as isopropyl myristate.
Although powdered aerosol compositions having good application characteristics are known in the art, it is continually desired to provide powdered aerosol compositions having improved application properties.
It is further desirable to provide powdered aerosol compositions having reduced mistiness and dustiness upon dispensation from an aerosol container.